Browsing by Author "Reddy, G.M.S."

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High temperature erosion performance of NiCrAlY/Cr2O3/YSZ plasma spray coatings
(Taylor and Francis Ltd., 2023) Reddy, G.M.S.; Prasad, C.D.; Patil, P.; Shetty, G.; Naresh, N.; Ramesh, M.R.
The current investigation's objective was to assess the air jet erosion tester's ability to measure the erosive behaviour of plasma sprayed coatings on titanium-15 alloy. 65% NiCrAlY, 30% Cr2O3, and 5% YSZ make up the coating's chemical composition. A study of microstructure and phases was carried out. Microhardness and adhesive strength have both been measured in this work. With impact angles of 30° and 90° at 300°C, 500°C, and 700°C, Al2O3 erodent was utilised in a solid particle erosion test. An optical profilometer was used to calculate the erosion volume loss. The coating erosion resistance was found to be higher than the substrate sample for the test temperature that was employed, and this was more obvious at higher impact angles and higher temperatures The ductile character of the coating is seen in the contour of the deteriorated coating surface. © 2023 Institute of Materials Finishing Published by Taylor & Francis on behalf of the Institute.
High-temperature oxidation behavior of plasma-sprayed NiCrAlY/TiO2 and NiCrAlY/Cr2O3/YSZ coatings on titanium alloy
(Springer Science and Business Media Deutschland GmbH, 2022) Reddy, G.M.S.; Prasad, C.D.; Shetty, G.; Ramesh, M.R.; Rao, T.N.; Patil, P.
The 70% NiCrAlY + 30% TiO2 and 70% NiCrAlY + 25% Cr2O3 + 5% YSZ metallic coatings are sprayed on titanium-15 alloy of ASTM B338, Grade 2, by using the plasma spray coating technology. Cyclic oxidation studies are conducted on the uncoated and coated alloys at 700 °C under static air environment. The kinetics of oxidation is studied by using the thermo-gravimetric method. Phase, microstructural, and chemical analysis tests are performed on as-sprayed and oxidized coatings. The coated alloys are found to be more resistant when compared to the uncoated alloys. The NiCrAlY + Cr2O3 + YSZ coating is found to be more protective when compared to NiCrAlY + TiO2 coating. It is concluded that the formation of Cr2O3, NiCr2O4, and Al2O3 is attributed to the development of oxidation resistance in the coatings. © 2022, International Institute of Welding.
Investigation of the effect of NiCrAlY/Cr2O3/YSZ plasma coatings on erosion performance of MDN 420 steel at high temperature
(Inderscience Publishers, 2023) Reddy, G.M.S.; Prasad, C.D.; Patil, P.; Shetty, G.K.; Kakur, N.; Ramesh, M.R.
The purpose of the current study was to use an air jet erosion tester to examine the erosive behaviour of plasma sprayed coatings on MDN-420 that were composed of 70% NiCrAlY, 25% Cr2O3, and 5% YSZ. Microstructure and phase studies were performed. Measurements were made on the microhardness and adhesion strength. Al2O3 erodent was used in a solid particle erosion test with impact angles of 30° and 90° at 300°C, 500°C, and 700°C. The erosion volume loss was measured using an optical profilometer. For the test temperature used, it was found that the coating’s erosion resistance was greater than that of the substrate and that it was more pronounced at higher impact angles and higher temperatures. The shape of the degraded coating surface reflects the coating’s ductile nature. © © 2023 Inderscience Enterprises Ltd.
Solid Particle Erosion Behaviour of Plasma-Sprayed (WC–Co)/(Cr3C2–NiCr) Coatings
(Springer Science and Business Media Deutschland GmbH, 2022) Reddy, G.M.S.; Ramesh, S.; Anne, G.; Ramesh, M.R.; Rao, T.N.; Patil, P.
This study reports the high-temperature erosion behaviour of plasma-sprayed 35% (WC–Co)/65% (Cr3C2–NiCr) coating on MDN-420 alloy. Plasma spray coatings have always played a pivotal role in enabling industries to combat problems of premature degradation of components that operate in harsh environments. (WC–Co) + (Cr3C2–NiCr) coating is investigated for erosion under various laboratory-simulated conditions. Coating surface is characterized by using an optical microscope, scanning electron microscope (SEM), and X-ray diffraction (XRD). Porosity, microhardness, surface roughness, and adhesion strength of the coating are measured. The solid particle erosion test is conducted at the temperatures of 300 °C, 500 °C and 700 °C with the impact angles of 30° and 90° by using Al2O3 as an erodent in the hot air jet erosion testing machine. The optical profilometer is used to evaluate the erosion volume loss of the coated and uncoated samples. It is observed that erosion resistance of the substrate is found to be higher than the coating at the different test temperatures. As the temperature increases, the erosion resistance of the coating is also increased at all the temperatures for both impact angles of 30° and 90°.The eroded coating surface morphology reveals that the generalized behaviour of the coating is ductile in nature. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.